Dwayne "The Rock" Johnson first rose to fame throwing down hard in the WWE ring, later making a name for himself in Hollywood with roles in action movies like the Fast and Furious series. Now, he stars in HBO’s testosterone-charged Ballers (and an ongoing Instagram series of Intense Gym Selfies). Despite building a career on the prototypical “tough guy” image, though, Johnson has always been remarkably real and vulnerable about his personal life, including his experience with depression.

On Wednesday night, the 45-year-old opened up about a tragedy from his past in a somber Instagram post. He shared a photo of himself filming an uncharacteristically emotional scene for Ballers, in which his character visits the grave of the brother he lost to suicide.

"Got me thinkin’ though bout how many of us have been affected by suicide of our friends, family," the actor wrote. "Struggle and pain is real. We’ve all been there on some level or another." And Johnson certainly has. He went on to reveal how his mother attempted suicide when he was a teenager. "My mom tried to check out when I was 15," he wrote. "She got outta the car on Interstate 65 in Nashville and walked into oncoming traffic. Big rigs and cars swerving outta the way not to hit her. I grabbed her and pulled her back on the gravel shoulder of the road."

Johnson wrote that he believes the fictional scene reflects the unfortunate reality that there are many people vulnerable to suicide who need help.

"It did [remind me] that we always gotta do our best to really pay attention when people are in pain," he wrote. "Help ‘em thru it, get ‘em talkin’ about the struggle and remind ‘em that they’re not alone. We got lucky that day when I was 15 and that ain’t always the case."

Letting people dealing with a mental illness like depression know they’re not alone is an extremely important message—and one that Johnson has spread before. "I found that, with depression, one of the most important things you could realize is that you're not alone," he shared on an episode of Oprah's Master Class in 2015. "You're not the first to go through it; you're not going to be the last to go through it. And oftentimes, it happens, you just feel like you're alone. You feel like it's only you. You're in your bubble. And I wish I had someone at that time who could just pull me aside and [say], 'Hey, it's gonna be OK. It'll be OK.'"

You can help prevent suicide by noticing when someone is struggling with their mental health and proactively reaching out to them—letting them know they’re not alone, like Johnson encourages.

According to the AFSP, "Most people who take their lives exhibit one or more warning signs, either through what they say or what they do." These warning signs include talking about suicide and feeling hopeless, trapped, burdensome, or like they have no reason to live. Changes in behavior include the subtle (e.g. an increase in drug or alcohol use, isolation and withdrawal, and changes in sleep) and the not so subtle (such as giving away their most meaningful belongings and saying goodbye to people).

If somebody you love shows signs that they’re thinking about ending their life or displays a worry change in behavior or mood, they need somebody’s help. And if you’re scared or uncertain about reaching out, there is guidance available to help you navigate the conversation. BeThe1To.com, a suicide prevention website from the National Action Alliance for Suicide Prevention and the National Suicide Prevention Lifeline, recommends five steps for approaching the situation, assisting them in getting the help they need, and following up to let them know you're still there for them.

No matter what’s going on with that person, they’re probably feeling very alone. And saying, "Are you OK?" or "I’m here for you" is a simple way to remind them they’re not.

If you or someone you know is struggling with suicidal thoughts, please contact the National Suicide Prevention Lifeline at 800-273-8255.